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Volume 85, Nº 5 (2024)
Articles
Biosocial effects of oxytocin in vertebrates: From hormonal reproductive functions to parochial altruism
Resumo
Oxytocin is an ancient neuropeptide with a wide range of functions. Over hundreds of millions years of evolution, the functional role of oxytocin and its homologues expanded from initially providing effective reproduction to consolidating partner relationships in monogamous species, family groups of cooperatively breeding species and diverse complex relationships within social groups characterized by parochial altruism traits. In different classes of vertebrates, the expansion of the scope of oxytocin actions could evolve independently, and today the most complete spectrum of functional effects of oxytocin is studied in mammals. The review gives a brief analysis of the functional role of oxytocin and its homologues in vertebrates based on modern research with an emphasis on its effects on social behavior.
345-371
The behaviour of lepidopteran miners while feeding and dispersing
Resumo
The trophic specialization of lepidopteran miners is associated with the life form (tree–bush–grass) and place of mining (upper or lower side of the leaf) of the host plant. Narrow specialization of miners at the level of plant genera determines the high efficiency of food consumption. The small size of miners limits the potential fertility of the species (compared to other lepidopterans) and the independent migratory activity of adults. The oviposition of one egg predominates. This behaviour of females ensures maximum distribution of offspring in space and reduces intraspecific competition of caterpillars.
372-385
The role of abiotic and biotic factors in population dynamics of lepidopteran miners
Resumo
The individual development of most species of lepidopteran miner caterpillars is associated with one plant specimen. The development of all permanent miners is limited to one leaf, most facultative miners – to one canopy. Unlike a free-living phyllophage, the leaf miner caterpillar cannot change the host plant, for example, if there is a shortage of food due to overpopulation. This determines the existence of mortality factors dependent on population density: both through intrapopulation competition of caterpillars and through the physiological state of the host plant. Among the representatives of the third trophic level, parasitoids are of greatest importance for the population dynamics of mining lepidopterans. The species diversity of miner parasitoid complexes among phytophagous insects is the highest. The functioning of the parasitoid complex is associated with structural and functional transformations over time. The mortality of caterpillars from pathogens is low.
386-403
Extended movements of particles in stolons of colonial hydroids of the family Campanulariidae
Resumo
The range of movement of food particles along the distribution system in colonies with a length of 8 stolon modules was studied in colonies of four species of hydroids from the Campanulariidae family (Gonothyraea loveni, Laomedea flexuosa, Obelia longissima, O. geniculata). Visual scanning, i.e. tracking under a microscope the movement of individual particles or their clusters along the gastrovascular cavity of the stolon was carried out continuously for 90 minutes for each of six to seven recording sessions. For the first time, the range and duration of movement of individual particles in the stolon cavity of the studied species in a state of trophic pause, which lasted a day, were established. The distribution system functions quite efficiently even during fasting. This is expressed in transcolonial continuous transfers of particles from one end of the colony to the opposite. The most extended movements of particles along the stolon of the colony occur relatively rarely: in G. loveni, L. flexuosa and O. geniculata from one to three times in 90 minutes, and in O. longissima 12 times in the same period. Against the backdrop of an abundance of short trajectories (more than 200 in 90 minutes), transcolonial movements of particles may be missed if registrations are not long enough, which was the basis for erroneous claims about the chaotic functioning of the distribution system.
404-422